Allergic Bronchopulmonary Aspergillosis

Allergic bronchopulmonary aspergillosis (ABPA) is an allergic or hypersensitive reaction to a fungus called “Aspergillus” fumigates. These fungi are found in the soil. Although Aspergillus are common, their reaction is rare in people with normal immune systems. However, when people with weak immune systems, underlying lung disease or asthma, inhale the fungal spores, they can cause serious illnesses. In some people, the spores may trigger allergic reactions, while in others, the development of mild to severe lung infections. The most severe form of aspergillosis is invasive and occurs when the infection spreads to blood vessels, kidneys, heart, or skin. Nevertheless, most strains of Aspergillus are harmless. Unfortunately, there is no cure for ABPA; the condition can only be managed.

Risk Factors

The risk of developing ABPA depends on the overall health and extends the exposure to the infestation. These factors may make more vulnerable to infection.

• Weakened Immune System.

People who are taking immune-suppressing drugs after transplantation surgery or people who are diagnosed with cancer and are on chemotherapy are at high risk of having a compromised immune system. Also, people in the interstage of AIDS may be at high risk.

• Low White Blood Cells [WBC] Levels.

People who had chemotherapy, organ transplant, or leukemia have low white blood cell levels. Those with a chronic granulomatous disease, an inherited disorder that affects the immune system cells, are also affected.

• Asthma or Cystic Fibrosis. 

Especially people with long-standing lung disorders.

• Lung Cavities.

People having air cavities in their lungs are at high risk of long-term corticosteroid therapy.

Complications of Allergic Bronchopulmonary Aspergillosis

ABPA can cause various serious complications, depending on the type of infections:

• Local emphysema
• Invasive aspergillosis
• Honeycomb fibrosis
• Chronic and recurrent lobar atelectasis
• Recurrent asthma exacerbations and steroid dependence
• Cavitation
• Recurrent pulmonary infections and hemoptysis[1][2][3].
• Systematic infection. 

The most severe complication is spreading the infection to other parts of your body, especially your brain, heart, and kidneys. This spread is rapid and may be fatal.

Prevention of ABPA

It is nearly impossible to avoid exposure to Aspergillus, but the determined effort may yield some success. If you have had a transplant or are undergoing chemotherapy, try to avoid where you are likely to encounter aspergillus infection, such as construction sites, compost piles, and buildings that store grain. Avoid activities that are in close contact with dust soil. Always wear a face mask to avoid mold exposure if you know that you have a weakened immune system. Use of antifungal medications to prevent the disease.

Diagnosis of ABPA

Aspergillus is present in all environments but poses a significant challenge to distinguish from certain other fungi under the microscope. Diagnosing an aspergilloma or invasive aspergillosis can therefore be difficult. The symptoms of ABPA also resemble those of lung disorders, such as tuberculosis.  To specify the cause of the symptoms, one or more of the following tests may be used:

• Aspergillus skin test.

It is most commonly used for diagnosing sensitization to Aspergillus. Fumigatus. An intradermal skin test is considered more sensitive than a skin prick test for diagnosing Aspergillus sensitization [4].

• Imaging Test

A chest X-ray or CT scan can show a fungal mass (aspergilloma), and the typical signs of ABPA.

• Sputum Test. 

This checks and confirms the presence of Aspergillus.

• Pulmonary Function Test.

Helps in measuring lung function impairment, its severity and post-treatment follow-up.

• Bronchoscopy.
• Tissue and Blood Tests. 

To look for antibodies (antigen) of Aspergillus, indicating an allergic response to confirm ABPA.

• Biopsy. 

Examining a sample of tissue from your lungs or sinuses under a microscope may confirm a diagnosis of invasive aspergillosis or ABPA. In addition, a needle biopsy or open lung biopsy can be done.

Treatment for Allergic Bronchopulmonary Aspergillosis

ABPA treatment varies with the type of disorder. The main aim of the treatment is to treat inflammation and reduce progressive lung injury. Possible treatments include the following:

• Observation. 

Simple, single aspergilloma usually does not need treatment. Instead, aspergillomas without symptoms should be closely monitored by chest X-ray. If the condition progresses, antifungal medication may be applied.

• Oral Corticosteroids. 

They are the primary therapy for ABPA. To prevent asthma or cystic fibrosis from worsening, oral corticosteroids may be combined with antifungal medications to reduce the dose of steroids and improve lung function. Prednisolone is the most commonly used drug for treatment.

• Antifungal Medication. 

The most effective treatment for ABPA is a newer antifungal drug, voriconazole (Vfend). Itraconazole is the most common drug used in the treatment of ABPA. Amphotericin B, nystatin, clotrimazole, miconazole is the next option. Antifungal drugs tend to exhibit adverse effects such as liver and kidney damage. Their interactions with other medications are also common.

• Antibiotics: To prevent or treat associated bacterial infections.
• Anti-IgE therapy [5]
• Surgery. 

Surgery is the first-choice treatment to remove the fungal mass when an aspergilloma causes bleeding in the lungs.

• Embolization. 

This procedure prevents further bleeding from the lungs caused by an aspergilloma. Material is injected through a catheter to harden and block the blood supply to the area to stop the bleeding. It is a temporary treatment as the bleeding can reoccur.   

Symptoms

The signs and symptoms of ABPA vary with the type of disease you develop. They include:

Allergic Reaction.

Some people with asthma or cystic fibrosis are allergic to aspergillus, and show the following signs:

• Fever.
• Cough with blood and mucus.
• Worsening previous asthma.

Aspergilloma

Some chronic lung conditions, like tuberculosis, emphysema, or advanced sarcoidosis, can develop air cavities in the lungs, and when such people are infected with aspergillus, fungus fibers may spread into the cavities and grow into tangled masses [fungus balls] known as aspergilloma. 

Initially, aspergillomas may cause a mild cough, but over time and when left untreated, can worsen the underlying chronic lung condition and probably cause:

• Cough with blood [hemoptysis]. 
• Shortened breaths.
• Wheezing.
• Fatigue.
• Weight loss.

Invasive Aspergillosis.

This is the most severe form of aspergillosis. It occurs when the infection extends rapidly from the lungs to the brain, heart, kidneys, or skin. 

It happens only in people with a weakened immune system resulting from cancer chemotherapy, bone marrow transplantation, or a disease of the immune system. If untreated, invasive aspergillosis can be deadly. Its signs depend on affected organs. In general, it can cause:

• Fever.
• Chills.
• Shortened breaths.
• Chest pain.
• Joint pain.
• Hemoptysis.
• Headaches.
• Eye problems.
• Skin lesions.

Other Types of Aspergillosis.

Apart from your lungs, aspergillus can invade other parts of your body [such as sinuses] and cause:

• Stuffy nose.
• Fever.
• Facial pains.
• Headaches.

Causes

You can not avoid aspergillus. It is found everywhere, in decaying leaves and compost, on plants, trees, and other crops. 

Most people have developed immunity to its effect, because of their healthy immune system. But to others with the weakened immune system from disease or immunosuppressant medications have fewer infections [fighting cells (white blood cells)]. Hence, aspergillus can invade the lungs and in the most severe cases, other parts of the body. It should, however, be noted that ABPA is not communicable from person to person. 

FAQ

1. Is ABPA life-threatening?

Allergic bronchopulmonary aspergillosis (ABPA) is a rare condition that may complicate asthma and cystic fibrosis. However, it is seldom seen as life-threatening.

2. Is ABPA curable?

There is no cure for ABPA. Treatment only refers to managing the condition, typically with corticosteroids taken orally or with puffers. Antifungal medication generally does not affect; it cannot penetrate the aspergillomas. People with ABPA should be monitored regularly to ensure their condition is successfully managed.

3. Is ABPA an automatic disease?

Allergic bronchopulmonary aspergillosis (ABPA) is a condition characterized by an immune system’s exaggerated response. A hypersensitivity response to the fungus, Aspergillus fumigates. It happens most often in individuals with asthma or cystic fibrosis.

4. How can you prevent ABPA?

To prevent aspergillosis:

• Try to avoid areas with much dust, like construction sites or evacuation sites.
• Avoid activities that involve close contact with soil or dust, such as building that store grain compost piles.
• Try to stay away from where you are likely to encounter aspergillosis infection.
• Always wear a face mask to avoid exposure to mold if you have a weakened immune system.

5. Is ABPA hereditary?

Cases of ABPA within families suggest common genetic bases with low penetrance. In one case series from India, 5% of cases were familial. However, more research is found in this area.

 

References:

1. Agarwal R. Allergic bronchopulmonary aspergillosis. 2009 Mar;135(3):805-826. [PubMed]
2. Maturu VN, Agarwal R. Acute Invasive Pulmonary Aspergillosis Complicating Allergic Bronchopulmonary Aspergillosis: Case Report and Systematic Review. 2015 Oct;180(3-4):209-15. [PubMed]
3. Lowes D, Chishimba L, Greaves M, Denning DW. Development of chronic pulmonary aspergillosis in adult asthmatics with ABPA. Respir Med. 2015 Dec;109(12):1509-15. [PubMed].
4. https://www.ncbi.nlm.nih.gov/books/NBK542329/#article-66555.s8
5. Agarwal R, Sehgal IS, Dhooria S, Aggarwal AN. Developments in the diagnosis and treatment of allergic bronchopulmonary aspergillosis. Expert Rev Respir Med. 2016 Dec;10(12):1317-1334. [PubMed]
6. https://emedicine.medscape.com/article/296052-clinical